Portion of a shoe midsole



FIG. 1 is a perspective view of a poriton of a shoe midsole showing my new design;

FIG. 2 is another perspective view thereof;

FIG. 3 is a rear elevational view thereof; and,

FIG. 4 is a side elevational view thereof.

The uneven broken line immediately adjacent to the shaded area represents an unclaimed boundary of the design. The uneven broken line showing of the remainder of the shoe is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a shoe midsole, as shown and described. 